Figure 4. An inhibitor of LRS-Rag interaction enhances muscle regeneration.

(A) C2C12 cells were induced to differentiate for 72 hours in the presence or absence of 4 μM BC-LI-0186 (0186) and subjected to measurement of differentiation index. Data were normalized to control (n = 3). (B) Mice were intraperitoneally injected with 0186 at 5 mg/kg body weight every 3 days. The first 0186 injection coincided with BaCl₂ injection into TA muscles. Muscles were isolated on day 7 after injury (D7AI) and day 14 after injury (D14AI), and subjected to measurement of CSA of regenerating myofibers. Data were presented as the size distribution of all myofibers with average (avg.) CSA (n = 5–6). (C) TA muscles from mice treated as in B were isolated on day 4 after injury and subjected to Western blotting analysis (n = 3). (D, E) Mice were intraperitoneally injected with 0186 at 5 mg/kg body weight every 3 days and with triciribine (TCB) at 1 mg/kg body weight every day. The first injection of 0186 and TCB coincided with BaCl₂ injection into TA muscles. Muscles were isolated on D14AI, weighed (D, n = 6–7), and subjected to measurement of CSA of regenerating myofibers (E, n = 6–7). (F–H) Mice treated as in B were subjected to in situ force measurements of regenerating TA muscles at D14AI (F, n = 7–8), followed by muscle weight measurement (G, n = 7–8). Maximum twitch force and tetanic force were converted to specific maximum twitch force and tetanic force as described in the Supplemental Methods (H, n = 7–8). All values were presented as relative to uninjured contralateral muscles. *P < 0.05, **P < 0.01 by 2-tailed paired t test (A) or 2-tailed unpaired t test (B, C, F–H). ^††P < 0.001 (D), ^†P < 0.005 (E) by 2-way ANOVA. All error bars represent SEM.